JP2012240817A - Gripping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gripping device that can grip a workpiece with a suitable gripping force corresponding to a hardness of the workpiece.SOLUTION: A gripping device 1 grips a workpiece 9 with a pair of arms 5. The pair of arms 5 has arm bases 5a. The pair of arm bases 5a can approach and separate each other. The distance of the pair of arm bases 5a can be changed by an opening/closing mechanism 3. One of the arms 5 has an intermediate member 5b approachably and separably provided on the arm bases 5a between the pair of arm bases 5a, an intermediate bias member which biases the intermediate member 5b toward the other arm 5, a contact member 5c approachably and separably provided on the intermediate member 5b so as to be contactable with the workpiece 9, and an end bias member that biases the contact member 5c toward the other arm 5 by the bias power different from the bias power of the intermediate bias member.

Description

  The present invention relates to a gripping device that grips a workpiece by a pair of arms.

  The gripping device described in Patent Literature 1 includes a pair of arms and an opening / closing mechanism that changes the interval between the pair of arms. Each arm has an arm base that is moved by an opening / closing mechanism, a grip plate that is movably attached to the arm base by a link mechanism, and a spring that biases the grip plate against the arm. A pair of arms are brought close to each other, the gripping plate hits the workpiece, the gripping plate moves upward and toward the arm base against the biasing force of the spring, and the gripping plate grips the workpiece by the biasing force of the spring.

  The arm of the gripping device described in Patent Literature 2 includes an arm base, a holder that is attached to the arm base so that a seesaw can be operated, a soft rubber plate that is attached to the upper portion of the holder, and a hard rubber plate that is attached to the lower portion of the holder. . When a plurality of workpieces are sandwiched between the arms, the lower workpiece is held by a hard rubber plate, and the upper workpiece is held by a soft rubber plate. Therefore, the gripping device can stably hold a plurality of stages of workpieces.

Japanese Patent Laid-Open No. 50-149052 Japanese Patent Laid-Open No. 2-81896

  However, the gripping device sometimes drops a workpiece when a heavy workpiece is gripped with a weak gripping force. On the other hand, when a soft work is gripped with a strong gripping force, the work may be damaged. Therefore, a gripping device that can grip a workpiece with a suitable gripping force according to the weight or hardness of the workpiece is conventionally required.

  In order to solve the above-mentioned problems, the present invention is a gripping device as described in each claim. According to one feature, the gripping device grips a workpiece with a pair of arms. Each of the pair of arms has an arm base. The pair of arm bases can approach and separate from each other, and the distance between the pair of arm bases is changed by an opening / closing mechanism. At least one arm has an intermediate member provided between the pair of arm bases so as to be able to approach and separate from the arm base, an intermediate urging member that urges the intermediate member toward the other arm, and the intermediate member A contact member that is provided so as to be able to approach and separate from each other and that can contact the workpiece, and a tip biasing member that biases the contact member toward the other arm by a biasing force having a magnitude different from the biasing force of the intermediate biasing member; Have

  Therefore, when the pair of arms are brought close to each other, the contact member hits the workpiece. The contact member receives a force against the biasing force of the tip biasing member, and the intermediate member receives a force against the biasing force of the intermediate biasing member. Since the biasing force of the tip biasing member and the biasing force of the intermediate biasing member are different, either the intermediate member or the contact member moves first against the small biasing force, and the workpiece is gripped with a small gripping force. A small gripping force state can be obtained. Further, when the pair of arms are brought close to each other, the movement of one member is restricted and the other member moves against a large biasing force, and a large gripping force state in which the workpiece is gripped by a large gripping force is obtained. Therefore, the gripping device can grip with a small gripping force without damaging a soft workpiece in a small gripping force state, and can securely grip without dropping a heavy workpiece in a large gripping force state.

  Therefore, according to the present invention, the gripping device can grip the workpiece with a suitable gripping force according to the weight or hardness of the workpiece.

It is a perspective view of a holding device. It is a perspective view of an arm and a work. It is a perspective view of an arm and a work in a small gripping force state. It is a perspective view of an arm and a work in a large gripping force state. It is a control block diagram of a holding device. It is a partial schematic top view of the holding | grip apparatus concerning another form. FIG. 7 is a partial schematic top view of the gripping device of FIG. 6 in a small gripping force state. FIG. 7 is a partial schematic top view of the gripping device of FIG. 6 in a small gripping force state. FIG. 7 is a partial schematic top view of the gripping device of FIG. 6 in a large gripping force state. FIG. 7 is a partial schematic top view of the gripping device of FIG. 6 in a large gripping force state. FIG. 7 is a partial schematic top view of the gripping device of FIG. 6 in a large workpiece large gripping force state. It is a disassembled perspective view of the arm concerning another form.

  One embodiment of the present invention will be described with reference to FIGS. The gripping device (conveying device) 1 has a base 2 and a pair of arms 5 as shown in FIG. The base 2 extends forward from a pair of columns 2a extending vertically, a lower beam 2b connecting the lower portions of the columns 2a, an upper beam 2c connecting the upper portions of the columns 2a, and the lower portions of the columns 2a. A leg 2d and a base 2f extending rearward of the column 2a at a position higher than the leg 2d are provided. Note that the vertical direction is the direction of gravity, and is the vertical direction in FIG. The front-rear direction is the traveling direction of the gripping device 1, the front is the right direction in FIG. 1, and the rear is the left direction in FIG. The left-right direction is a direction that is orthogonal to the traveling direction of the gripping device 1 and is horizontal.

  As shown in FIG. 1, a wheel 2e is attached to the lower side of the tip of the leg 2d so as to be able to roll. Wheels 2g are attached to the lower sides of the left and right parts of the base 2f so as to be able to roll. A battery 7 and a control device 2i are mounted on the base 2f. A handle 2h extending upward from the table 2f is provided at the rear part of the table 2f. An operation panel 2j is attached to the handle 2h. A lifter 6 and an opening / closing mechanism 3 are provided at the front portion of the base 2.

  As shown in FIG. 1, the lifter 6 includes a male screw member 6a, a female screw member 6b, and a motor 6d. The male screw member 6a extends in the vertical direction, and the upper and lower end portions are attached to the upper beam 2c and the lower beam 2b so as to be axially rotatable. The female screw member 6b is screwed into the male screw member 6a. The opening / closing mechanism 3 is attached to the female screw member 6b via a bracket 6c. The motor 6d is attached to the lower beam 2b and rotates the male screw member 6a by the electric power supplied from the battery 7. As the male screw member 6a rotates, the female screw member 6b moves up and down along the male screw member 6a.

  The opening / closing mechanism 3 has a mechanism base 3a and a male screw member 3b as shown in FIG. The mechanism base 3a extends in the left-right direction, and the left and right ends are attached to the column 2a so as to be movable in the vertical direction. The mechanism base 3 a is attached to the female screw member 6 b of the lifter 6 by the bracket 6 c and is moved up and down by the lifter 6. The male screw member 3b extends in the left-right direction, and the left and right end portions are attached to the mechanism base 3a so as to be rotatable.

  The opening / closing mechanism 3 further includes a pair of female screw members 3c and a motor 3d as shown in FIG. The female screw member 3c is screwed to the male screw member 3b. The motor 3 d is attached to the mechanism base 3 a and rotates the male screw member 3 b with the electric power supplied from the battery 7. The male screw member 3b and the pair of female screw members 3c are formed with a male screw and a female screw so that the pair of female screw members 3c approach and separate from each other by the axial rotation of the male screw member 3b.

  As shown in FIG. 2, the arm 5 has an arm base 5a, an intermediate member 5b, and a contact member 5c. The arm base 5a, the intermediate member 5b, and the contact member 5c are substantially plate-shaped, and are erected and arranged in parallel. The arm base 5 a extends in the front-rear direction, and the rear part is attached to the female screw member 3 c of the opening / closing mechanism 3.

  The arm base 5a and the intermediate member 5b are connected by an intermediate link mechanism 5d as shown in FIG. The intermediate link mechanism 5d has intermediate links 5d1 and 5d2 arranged in parallel in the vertical direction. One end portions of the intermediate links 5d1 and 5d2 are attached to the arm base 5a so as to be rotatable in the vertical direction. The other end portions of the intermediate links 5d1 and 5d2 are attached to the intermediate member 5b so as to be vertically rotatable at a position higher than the one end portion. The upper and lower intermediate links 5d1 and 5d2 are provided at both the front part of the arm base 5a and the rear part of the arm base 5a.

  The intermediate member 5b and the contact member 5c are connected by a tip link mechanism 5e as shown in FIG. The front end link mechanism 5e has front end links 5e1 and 5e2 arranged vertically. One end portions of the tip links 5e1 and 5e2 are attached to the intermediate member 5b so as to be rotatable in the vertical direction. The other end portions of the distal end links 5e1 and 5e2 are attached to the contact member 5c so as to be vertically rotatable at a position higher than the one end portion. The upper and lower end links 5e1 and 5e2 are provided at both the front part of the intermediate member 5b and the rear part of the intermediate member 5b.

  As shown in FIG. 2, the arm 5 includes an intermediate biasing member 5f and a tip biasing member 5g. The intermediate biasing member 5f has one end portion attached to the arm base 5a and the other end portion attached to the intermediate member 5b above the one end portion. The intermediate biasing member 5f is a tension spring and biases the intermediate member 5b downward and away from the arm base 5a.

  The tip biasing member 5g has one end attached to the intermediate member 5b and the other end attached to the contact member 5c above the one end as shown in FIG. The tip biasing member 5g is a tension spring, and biases the contact member 5c downward and away from the intermediate member 5b.

  The biasing force of the tip biasing member 5g is smaller than the biasing force of the intermediate biasing member 5f. Specifically, the spring constant of the tip biasing member 5g is smaller than the spring constant of the intermediate biasing member 5f. Therefore, the urging force of the tip urging member 5g is smaller than the urging force of the intermediate urging member 5f when elastically deformed by the same length. Therefore, the biasing force that the tip biasing member 5g biases the contact member 5c in the horizontal direction is smaller than the biasing force that the intermediate biasing member 5f biases the intermediate member 5b in the horizontal direction.

  As shown in FIG. 2, an intermediate member sensor 4a that detects that the distance between the intermediate member 5b and the arm base 5a has become a predetermined value or less is provided between the intermediate member 5b and the arm base 5a. The intermediate member sensor 4a is a switch sensor, and transmits a detection signal when it is pushed by the intermediate links 5d1, 5d2 or the intermediate member 5b when the intermediate member 5b comes close to the arm base 5a.

  As shown in FIG. 2, a contact member sensor 4b that detects that the distance between the contact member 5c and the intermediate member 5b has become a predetermined value or less is provided between the contact member 5c and the intermediate member 5b. The contact member sensor 4b is a switch sensor, and transmits a detection signal when pushed by the end links 5e1 and 5e2 or the contact member 5c when the contact member 5c comes close to the intermediate member 5b.

  The intermediate member sensor 4a and the contact member sensor 4b are electrically connected to the control device 2i as shown in FIG. An operation panel 2j and motors 3d and 6d are electrically connected to the control device 2i. Information or the like for the workpiece is input to the operation panel 2j by the worker, and an information signal corresponding to the information is transmitted to the control device 2i. The control device 2i controls the motors 3d and 6d based on information signals from the operation panel 2j and detection signals from the intermediate member sensor 4a and the contact member sensor 4b.

  When the workpiece 9 is gripped by the gripping device 1, the gripping device 1 is moved to the vicinity of the shelf 10 by the wheels 2e as shown in FIGS. The operation panel 2j is operated, the control device 2i controls the lifter 6 based on a signal from the operation panel 2j, and the arm 5 moves to the height of the workpiece 9. Information such as the hardness or weight of the workpiece 9 is input from the operation panel 2j by the operator.

  When determining that the workpiece 9 is soft or light based on the information signal transmitted from the operation panel 2j, the control device 2i brings the pair of arms 5 close by the opening / closing mechanism 3 as shown in FIGS. The contact member 5c comes into contact with the workpiece 9, and the contact member 5c moves toward and rises toward the intermediate member 5b against the biasing force of the tip biasing member 5g.

  The tip urging member 5g has a smaller urging force than the intermediate urging member 5f and is deformed more than the intermediate urging member 5f. Therefore, the movement amount of the contact member 5c with respect to the intermediate member 5b is larger than the movement amount of the intermediate member 5b with respect to the arm base 5a. As shown in FIGS. 2 and 3, the contact member 5 c grips the work 9 and lifts the work 9. Thereby, the work 9 is lifted with respect to the shelf 10.

  As shown in FIG. 3, the contact member 5c or the tip link mechanism 5e hits the intermediate member 5b, and the movement of the contact member 5c to the intermediate member 5b is restricted. The tip link mechanism 5e presses the contact member sensor 4b, and the contact member sensor 4b transmits a detection signal to the control device 2i (see FIG. 5). The control device 2 i controls the opening / closing mechanism 3 based on the detection signal from the contact member sensor 4 b to maintain the distance between the pair of arms 5. As a result, the pair of arms 5 grips the workpiece 9 with a small gripping force.

  When determining that the workpiece 9 is heavy or hard based on the information signal from the operation panel 2j, the control device 2i brings the pair of arms 5 closer by the opening / closing mechanism 3 as shown in FIGS. As a result, the intermediate member 5b moves and rises toward the arm base 5a against the urging force of the intermediate urging member 5f. The intermediate urging member 5f has a larger urging force than the tip urging member 5g, and strongly urges the intermediate member 5b toward the workpiece 9. For this reason, the contact member 5c is strongly applied to the workpiece 9, and the contact member 5c grips the workpiece 9 strongly.

  As shown in FIG. 4, the intermediate member 5b is restricted from moving to the arm base 5a when the intermediate member 5b or the intermediate link mechanism 5d hits the arm base 5a. The intermediate link mechanism 5d pushes the intermediate member sensor 4a, and the intermediate member sensor 4a transmits a detection signal to the control device 2i (see FIG. 5). The control device 2 i controls the opening / closing mechanism 3 based on the detection signal from the intermediate member sensor 4 a to maintain the distance between the pair of arms 5. As a result, the pair of arms 5 grips the workpiece 9 with a large gripping force.

  As described above, the gripping device 1 grips the workpiece 9 with the pair of arms 5 as shown in FIG. Each of the pair of arms 5 has an arm base 5a. The pair of arm bases 5a can be moved close to and away from each other. One arm 5 includes an intermediate member 5b provided between the pair of arm bases 5a so as to be able to approach and separate from the arm base 5a, and an intermediate urging member 5f that urges the intermediate member 5b toward the other arm 5. The contact member 5c that is provided so as to be able to approach and separate from the intermediate member 5b and that can contact the workpiece 9, and the urging force that is different from the urging force of the intermediate urging member 5f is used to connect the contact member 5c to the other arm. And a front end urging member 5 g that urges toward 5.

  Therefore, when the pair of arms 5 are brought close to each other, the contact member 5 c hits the work 9. The contact member 5c receives a force against the biasing force of the tip biasing member 5g, and the intermediate member 5b receives a force against the biasing force of the intermediate biasing member 5f. Since the urging force of the tip urging member 5g and the urging force of the intermediate urging member 5f are different, either one of the intermediate member 5b and the contact member 5c (contact member 5c) moves first against the small urging force. Thus, a small gripping force state in which the workpiece 9 can be gripped with a small gripping force is obtained. Further, when the pair of arms 5 are brought close to each other, the movement of one member (contact member 5c) is restricted, and the other member (intermediate member 5b) moves against a large biasing force, and the workpiece 9 is moved by a large gripping force. A large gripping force state for gripping is obtained. Therefore, the gripping device 1 can grip with a small gripping force without damaging the soft workpiece 9 in the small gripping force state, and can securely grip the heavy workpiece 9 without dropping in the large gripping force state.

  As shown in FIG. 2, the gripping device 1 includes intermediate links 5d1 and 5d2 arranged vertically between the arm base 5a and the intermediate member 5b, and vertically arranged between the intermediate member 5b and the contact member 5c. It has tip links 5e1 and 5e2 provided. Each of the intermediate links 5d1 and 5d2 is connected to the arm base 5a and the intermediate member 5b so that the connecting portion of the intermediate member 5b is above the connecting portion of the arm base 5a and is rotatable in the vertical direction. Each of the end links 5e1 and 5e2 is connected to the intermediate member 5b and the contact member 5c so that the connecting portion in the contact member 5c is above the connecting portion in the intermediate member 5b and is rotatable in the vertical direction.

  Accordingly, the intermediate links 5d1 and 5d2 connect the intermediate member 5b to the arm base 5a so as to be movable. The distal links 5e1 and 5e2 connect the contact member 5c to the intermediate member 5b so as to be movable. When the pair of arms 5 are brought close to each other, the contact member 5c comes into contact with the workpiece 9, the contact member 5c rises with respect to the intermediate member 5b by the tilt of the end links 5e1 and 5e2, and the intermediate member 5b tilts the intermediate links 5d1 and 5d2. Is raised with respect to the arm base 5a. Accordingly, the workpiece 9 is lifted up greatly because it is lifted by the two-step tilt of the tip links 5e1 and 5e2 and the intermediate links 5d1 and 5d2. For example, the work 9 can be lifted greatly without increasing the configuration of the arm 5 as compared with a structure in which the work 9 is lifted by a single-stage link.

  The intermediate biasing member 5f and the tip biasing member 5g are springs, and the spring constants of the spring as the intermediate biasing member 5f and the spring as the tip biasing member 5g are different. Therefore, the urging force of the intermediate urging member 5f and the urging force of the tip urging member 5g can be changed by the difference in spring constant.

  As shown in FIG. 2, the gripping device 1 includes a contact member sensor 4b that detects the distance between the contact member 5c and the intermediate member 5b, and an intermediate member sensor 4a that detects the distance between the intermediate member 5b and the arm base 5a. . When it is determined that the distance between the contact member 5c and the intermediate member 5b or the distance between the intermediate member 5b and the arm base 5a is not more than a predetermined value, the opening / closing mechanism 3 is stopped and the distance between the pair of arms is maintained ( A control device 2i (shown in FIG. 1).

  Accordingly, one of the intermediate member 5b and the contact member 5c (contact member 5c) moves first against the biasing force that is smaller of the biasing force of the intermediate biasing member 5f or the tip biasing member 5g. The control device 2i determines a small gripping force state when the movement of the previously moved member is restricted or before being restricted based on a detection signal from any one of the sensors 4a and 4b. The opening / closing mechanism 3 is stopped and the small gripping force state is maintained. The other one (intermediate member 5b) moves against the biasing member having a large biasing force, and when the movement is restricted or before the restriction, the other one of the sensors 4a, 4a, The control device 2i makes a determination based on the detection signal from 4b, and the control device 2i stops the opening / closing mechanism 3 to maintain the large gripping force state.

  The present invention is not limited to the above-described embodiment. For example, the gripping device 1 may have an arm 12 shown in FIGS. 6 to 11 instead of the arm 5 shown in FIG. As shown in FIG. 6, the arm 12 has an arm base 12a, an intermediate member 12b, a first contact member 12c, and a second contact member 12h. The arm base 12 a extends in the front-rear direction, and a rear end portion is attached to the female screw member 3 c of the opening / closing mechanism 3.

  As shown in FIG. 6, an intermediate link mechanism 12d and an intermediate urging member 12f are provided between the arm base 12a and the intermediate member 12b. The intermediate link mechanism 12d has upper and lower intermediate links that movably connect the intermediate member 12b and the arm base 12a. The intermediate biasing member 12f biases the intermediate member 12b toward the first contact member 12c and downward. A tip link mechanism 12e and a tip biasing member 12g are provided between the intermediate member 12b and the first contact member 12c. The tip link mechanism 12e has upper and lower tip links that movably connect the first contact member 12c and the intermediate member 12b. The tip biasing member 12g biases the first contact member 12c toward the other arm 12 and downward.

  As shown in FIG. 6, the second contact member 12h is provided at the front end of the arm base 12a. Between the arm base 12a and the second contact member 12h, a side-by-side link mechanism 12i and a side-by-side biasing member 12j are provided. The side-by-side link mechanism 12i has upper and lower side-by-side links that movably connect the second contact member 12h and the arm base 12a. The side-by-side biasing member 12j biases the second contact member 12h toward the other arm 12 and downward. The second contact member 12h is juxtaposed with the intermediate member 12b and is installed at a position closer to the arm base 12a than the first contact member 12c.

  As shown in FIGS. 6 to 11, the tip biasing member 12g generates a biasing force smaller than that of the intermediate biasing member 12f and the parallel biasing member 12j. The biasing force of the tip biasing member 12g is, for example, half or less that of the intermediate biasing member 12f. The urging forces of the intermediate urging member 12f and the side-by-side urging member 12j are, for example, substantially the same. The tip biasing member 12g, the intermediate biasing member 12f, and the side-by-side biasing member 12j are tension springs. The spring constant of the tip biasing member 12g is smaller than the spring constant of the intermediate biasing member 12f and the spring constant of the parallel biasing member 12j.

  As shown in FIG. 7, when the workpiece 9a is small and soft, the control device operates the opening / closing mechanism 3, and the first contact member 12c contacts the workpiece 9a. The first contact member 12c moves and rises toward the intermediate member 12b against the biasing force of the tip biasing member 12g. The contact member sensor detects that the movement of the first contact member 12c is regulated by the intermediate member 12b, and transmits a detection signal. The control device holds the distance of the arm 12 based on the detection signal, and the arm 12 grips the workpiece 9a with a small gripping force.

  As shown in FIG. 8, when the workpiece 9b is large and soft, the control device holds the distance of the arm 12 based on the detection signal as described above. At this time, a gap 12k is formed between the second contact member 12h and the workpiece 9b. Or although the clearance gap 12k is not formed, the 2nd contact member 12h does not push the workpiece | work 9b with a force stronger than the 1st contact member 12c. As a result, a large force is not applied to the workpiece 9b.

  When the work 9c is small and heavy, the gripping device 1 grips the work 9c by the method shown in FIG. 9 or the method shown in FIG. In the method of FIG. 9, the control device operates the opening / closing mechanism 3, and the first contact member 12c contacts the workpiece 9c. The first contact member 12c moves and rises toward the intermediate member 12b against the biasing force of the tip biasing member 12g. The intermediate member 12b moves and rises toward the arm base 12a against the urging force of the intermediate urging member 12f. The intermediate member sensor detects that the movement of the first contact member 12c is regulated by the arm base 12a and transmits a detection signal. The control device holds the distance of the arm 12 based on the detection signal, and the arm 12 grips the work 9c with a large gripping force.

  In the method of FIG. 10, the control device operates the opening / closing mechanism 3, and the second contact member 12h contacts the workpiece 9c. The second contact member 12h moves and rises toward the arm base 12a against the biasing force of the side-by-side biasing member 12j. The second contact member sensor detects that the movement of the second contact member 12h is regulated by the arm base 12a and transmits a detection signal. The control device holds the distance of the arm 12 based on the detection signal, and the arm 12 grips the work 9c with a large gripping force.

  As shown in FIG. 11, when the workpiece 9d is large and heavy, the control device operates the opening / closing mechanism 3, and the first contact member 12c contacts the workpiece 9d. The first contact member 12c moves and rises toward the intermediate member 12b against the biasing force of the tip biasing member 12g. The intermediate member 12b moves and rises toward the arm base 12a against the urging force of the intermediate urging member 12f. The second contact member 12h contacts the workpiece 9d, and the second contact member 12h moves toward the arm base 12a and rises against the urging force of the side-by-side urging member 12j. The second contact member sensor detects that the movement of the second contact member 12h is regulated by the arm base 12a and transmits a detection signal. The control device holds the distance of the arm 12 based on the detection signal, and the arm 12 grips the workpiece 9d with a large gripping force.

  As described above, the gripping device 1 is close to the first contact member 12c and the arm base 12a of one arm 12 between the pair of arms 12 separately from the first contact member 12c as shown in FIG. And a second contact member 12 h that is provided so as to be separable and that can contact the workpiece, and a parallel urging member 12 j that urges the second contact member 12 h toward the other arm 12. Accordingly, the gripping device 1 can grip the workpiece using one or both of the first contact member 12c and the second contact member 12h.

  As shown in FIG. 6, the arm base 12a extends forward from the opening / closing mechanism 3, and the first contact member 12c and the second contact member 12h are juxtaposed in the front-rear direction. Therefore, by adjusting the front / rear position of the arm base 12a with respect to the workpiece, the workpiece can be selected so that the workpiece can be gripped by any one of the first contact member and the second contact member.

  As shown in FIG. 6, the second contact member 12 h is closer to the arm base 12 a than the first contact member 12 c in a state where the workpiece is not gripped by the pair of arms 12. Therefore, when the arm 12 is brought close to the workpiece and the first contact member 12c hits the workpiece, the second contact member 12h can be surely avoided from hitting the workpiece. Therefore, it is possible to reliably obtain a state in which the workpiece can be gripped only by the first contact member 12c (see FIG. 7).

  As shown in FIGS. 6 and 8, the work 9d comes into contact with the first contact member 12c by bringing the pair of arms 12 close to each other, and either the movement of the first contact member 12c relative to the intermediate member 12b or the movement of the intermediate member 12b relative to the arm base 12a is performed. The distance from the workpiece contact surface of the first contact member 12c to the arm base 12a when the forward movement is restricted is longer than the distance from the workpiece contactable surface of the second contact member 12h.

  Therefore, a small gripping force state in which any one of the first contact member 12c and the intermediate member 12b moves first against the biasing force that is smaller of the biasing force of the intermediate biasing member 12f and the tip biasing member 12g is ensured. Can be obtained (see FIG. 8). Also, a large workpiece large gripping force state shown in FIG. 11 is obtained in which the other one moves against the biasing member having a large biasing force and the second contact member 12h moves against the parallel biasing member 12j. . Thus, the gripping device 1 can securely grip the large workpiece 9d.

  The gripping device 1 may have an arm 13 shown in FIG. 12 instead of the arm 5 shown in FIG. The arm 13 includes an arm base 13a, an intermediate member 13b, and a contact member 13c. The arm base 13a is plate-shaped and faces in the front-rear direction. One region 13 a 2 of the left and right regions of the arm base 13 a is attached to the female screw member 3 c of the opening / closing mechanism 3. A plurality of guide holes 13a1 are formed in the other region of the arm base 13a. The guide hole 13a1 extends in the vertical direction, and extends in a curved line or a straight line so that the lower part is positioned closer to the other arm 13 than the upper part.

  As shown in FIG. 12, a plate-like intermediate member 13b is provided in parallel on the front side of the arm base 13a. A plate-like attachment member 13f is provided in parallel on the rear side of the arm base 13a. A plurality of guide pins 13b1 are attached to one region of the left and right regions of the intermediate member 13b. The guide pin 13b1 extends rearward from the intermediate member 13b and passes through the guide hole 13a1 of the arm base 13a. The distal end portion of the guide pin 13b1 is screwed into the mounting hole 13f1 of the mounting member 13f. Thereby, the intermediate member 13b is attached to the arm base 13a so as to be movable in the vertical direction and the horizontal direction.

  As shown in FIG. 12, a plurality of guide holes 13b2 are formed in other regions of the intermediate member 13b. The guide hole 13b2 extends in the up-down direction, and extends in a curved line or a straight line so that the lower part is positioned near the other arm 13 from the upper part. A contact member 13c is provided on the front side of the guide hole 13b2 of the intermediate member 13b. A plate-like attachment member 13g is provided on the rear side of the guide hole 13b2 of the intermediate member 13b.

  As shown in FIG. 12, the contact member 13c has a base portion 13c1 provided in parallel with the intermediate member 13b and a front portion 13c2 extending forward from the front surface of the base portion 13c1. The front portion 13c2 is plate-shaped and faces the workpiece 9. A plurality of guide pins 13c3 are attached to the base portion 13c1. The guide pin 13c3 extends rearward from the base portion 13c1 and penetrates the guide hole 13b2 of the intermediate member 13b. The distal end portion of the guide pin 13c3 is screwed into the mounting hole 13g1 of the mounting member 13g. Thereby, the contact member 13c is attached to the intermediate member 13b so as to be movable in the vertical direction and the horizontal direction.

  As shown in FIG. 12, the arm 13 further includes an intermediate biasing member 13d and a tip biasing member 13e. The intermediate urging member 13 d is attached to the arm base 13 a and the intermediate member 13 b and urges the intermediate member 13 b toward the other arm 13. The tip urging member 13 e is attached to the intermediate member 13 b and the contact member 13 c and urges the tip urging member 13 e toward the other arm 13. The intermediate biasing member 13d and the tip biasing member 13e are tension springs, and the spring constant of the intermediate biasing member 13d is larger than the spring constant of the tip biasing member 13e.

  As shown in FIG. 12, the gripping device 1 brings the pair of arms 13 close to each other by the opening / closing mechanism 3 when gripping the workpiece 9. The contact member 13c comes into contact with the workpiece 9, and the contact member 13c approaches the intermediate member 13b and rises against the urging force of the tip urging member 13e. The contact member sensor detects that the distance between the contact member 13c and the intermediate member 13b is equal to or less than the set value, and the contact member sensor transmits a detection signal to the control device. When the control device determines that the workpiece 9 is soft based on the information signal from the operation panel, the control device holds the distance of the arm 13 by the opening / closing mechanism 3 based on the detection signal from the contact member sensor. As a result, the arm 13 grips the workpiece 9 with a small gripping force.

  As shown in FIG. 12, when the control device determines that the workpiece 9 is heavy or hard based on the information signal from the operation panel, the pair of arms 13 are brought closer to each other by the opening / closing mechanism 3. The intermediate member 13b approaches the arm base 13a and rises against the urging force of the intermediate urging member 13d. The intermediate member sensor detects that the distance between the intermediate member 13b and the arm base 13a is equal to or less than the set value, and the intermediate member sensor transmits a detection signal to the control device. The control device holds the distance of the arm 13 by the opening / closing mechanism 3 based on the detection signal. As a result, the arm 13 grips the workpiece 9 with a large gripping force.

  The gripping device 1 has a pair of arms 5, 12, and 13, each arm 5, 12, and 13 having arm bases 5a, 12a, and 13a, intermediate members 5b, 12b, and 13b, and contact members 5c, 12c, and 13c. Alternatively, only one arm 5, 12, 13 may have this configuration, and the other one arm may have another configuration. For example, a configuration in which another arm has only an arm base, or a configuration having an arm base and an intermediate member and no contact member may be employed.

  The opening / closing mechanism 3 may move the pair of arms 5, 12, 13 or may move only one arm 5, 12, 13.

  The arm base 5a and the intermediate member 5b may be plate-shaped or may have other configurations such as a plurality of rod members.

  The biasing force of the intermediate biasing members 5f, 12f, and 13d may be larger or smaller than the biasing force of the tip biasing members 5g, 12g, and 13e. For example, the spring constants of the intermediate biasing members 5f, 12f, and 13d may be smaller than the spring constants of the tip biasing members 5g, 12g, and 13e. When the urging force of the intermediate urging members 5f, 12f, and 13d is smaller than the urging force of the tip urging members 5g, 12g, and 13e, when the contact members 5c, 12c, and 13c hit the workpiece, the intermediate members 5b, 12b, and 13b The movement with respect to the arm bases 5a, 12a, and 13a moves largely before the movement of the contact members 5c, 12c, and 13c with respect to the intermediate members 5b, 12b, and 13b. The distance between the intermediate members 5b, 12b, and 13b and the arm bases 5a, 12a, and 13a is equal to or less than the installation value, and the pair of arms 5, 12, and 13 can hold the workpiece with a small gripping force by maintaining this state. . Further, the pair of arms 5, 12, 13 are brought close to each other, the distance between the contact members 5 c, 12 c, 13 c and the intermediate members 5 b, 12 b, 13 b is less than the set value, and this state is maintained, so that the pair of arms 5 The workpiece 9 can be held with a large gripping force.

  The intermediate urging members 5f, 12f, and 13d and the tip urging members 5g, 12g, and 13e may be springs, hydraulic cylinders, rubber, or the like. The intermediate urging members 5f, 12f, and 13d and the tip urging members 5g, 12g, and 13e may be installed at substantially the same angle with respect to the horizontal line, and the inclination with respect to the horizontal line is different. The horizontal urging force and the horizontal urging force by the tip urging member 5g may be different.

  The intermediate member 5b may be connected to the arm base 5a by an intermediate link mechanism 5d, or may be connected by a rail so as to be movable only in the horizontal direction or horizontally and vertically. The contact member 5c may be connected to the intermediate member 5b by a distal end link mechanism 5e, or may be connected by a rail so as to be movable only in the horizontal direction or horizontally and vertically.

  The second contact member 12h may be positioned on the front side of the first contact member 12c, or may be positioned on the rear side, the upper side, or the lower side of the first contact member 12c.

  The intermediate member sensor 4a and the contact member sensor 4b may be switch sensors or potentiometers that measure the angles of the intermediate links 5d1 and 5d2 or the tip links 5e1 and 5e2.

  The gripping device 1 has a distance measurement sensor that measures the distance between the arm base 5a and the intermediate member 5b or the distance between the arm base 5a and the contact member 5c, instead of the intermediate member sensor 4a and the contact member sensor 4b. The control device may determine the small gripping force state and the large gripping force state based on the detection signal from the measurement sensor.

  The arms 5, 12, 13 may have one intermediate member 5b, 12b, 13b between the arm base 5a, 12a, 13a and the contact member 5c, 12c, 13c, or two or more intermediate members. You may have.

DESCRIPTION OF SYMBOLS 1 Grasping device 2 Base 2i Control device 2j Operation panel 3 Opening / closing mechanism 3d, 6d Motor 4a Intermediate member sensor 4b Contact member sensor 5, 12, 13 Arm 5a, 12a, 13a Arm base 5b, 12b, 13b Intermediate member 5c, 12c, 13c Contact members 5d, 12e Intermediate link mechanisms 5d1, 5d2 Intermediate links 5e, 12e End link mechanisms 5e1, 5e2 End links 5f, 12f, 13d Intermediate bias members 5g, 12g, 13e Tip bias members 6 Lifters 9, 9a ˜9d Workpiece 12h Second contact member 12i Side-by-side link mechanism 12j Side-by-side biasing member 12k Clearance

Claims (8)

A gripping device for gripping a workpiece with a pair of arms,
Each of the pair of arms has an arm base, the pair of arm bases can be approached and separated from each other, and an interval between the pair of arm bases is changed by an opening / closing mechanism,
At least one of the arms includes an intermediate member provided between the pair of arm bases so as to be able to approach and separate from the arm base, and an intermediate urging member that urges the intermediate member toward the other arm. The contact member is provided so as to be close to and away from the intermediate member and can contact the workpiece, and the contact member is directed to the other arm by an urging force having a magnitude different from the urging force of the intermediate urging member. And a tip biasing member that biases the gripping device. The gripping device according to claim 1,
An intermediate link arranged vertically between the arm base and the intermediate member, and a tip link arranged vertically between the intermediate member and the contact member;
Each of the intermediate links is connected to the arm base and the intermediate member so that the connecting portion of the intermediate member is on the upper side of the connecting portion of the arm base, and is rotatable in the vertical direction.
Each of the end links is a gripping device that is connected to the intermediate member and the contact member so that the connection portion of the contact member is on the upper side of the connection portion of the intermediate member and is rotatable in the vertical direction. The gripping device according to claim 1 or 2,
The intermediate urging member and the tip urging member are springs, respectively, and the spring as the intermediate urging member and the spring as the tip urging member have different spring constants. The gripping device according to any one of claims 1 to 3,
The first contact member, which is the contact member, and the arm base of the one arm separately from the first contact member so as to be able to approach and separate between the pair of arms and to contact the workpiece A gripping device comprising: a possible second contact member; and a side-by-side biasing member that biases the second contact member toward the other arm. The gripping device according to claim 4,
A gripping device in which the arm base extends forward from the opening / closing mechanism, and the first contact member and the second contact member are arranged in parallel in the front-rear direction. The gripping device according to claim 4 or 5,
The gripping device in which the second contact member is closer to the arm base than the first contact member in a state where the workpiece is not gripped by the pair of arms. The gripping device according to claim 6,
When the pair of arms are brought close to each other and the workpiece hits the first contact member, the movement of either the movement of the first contact member relative to the intermediate member or the movement of the intermediate member relative to the arm base is restricted. The distance between the workpiece contact surface of the first contact member and the arm base is longer than the distance of the workpiece contactable surface of the second contact member. A gripping device according to any one of claims 1 to 7,
A contact member sensor for detecting a distance between the contact member and the intermediate member; and an intermediate member sensor for detecting a distance between the intermediate member and the arm base.
When it is determined that the distance between the contact member and the intermediate member or the distance between the intermediate member and the arm base is less than or equal to a predetermined value, the opening / closing mechanism is stopped and the distance between the pair of arms is maintained. A gripping device having a control device.

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